How will Grendel's view on the world it's divided into affect him?

Grendel himself adopts existentialism and asserts, “I alone exist.” He has rejected the philosophies of the Shaper, the dragon, and the priests; he returns to a world in which he is the center and the decider of meaning. His reality divides into “things to be murdered, and things that would hinder the murder of things.”

Grendel’s existentialism is a violent one, which allows him to succumb to the urges that have boiled in his heart from the first moment humans mistreated him. In a world without the Shaper, Grendel’s only choice is to kill wherever and whatever he can.